Antibodies against HIV are potential drugs that may be able to prevent HIV infection in humans. However, the long-term protective capacity of antibodies against HIV has not been assessed. We are using the pathogenic simian/human immunodeficiency virus (SHIV) model to test protective efficacy of these anti-HIV-1 bnAbs to prevent mucosal viral transmission.We have recently shown that one single injection of bnAbs can lead to durable protection from multiple SHIV challenges that can last up to 23 weeks. In addition we have also shown that early treatment with antibodies can halt SHIV infection in infant macaques and also can suppress viremia.